The main goal of the video-monitoring is to verify the effectiveness to the fish transit and that this condition persists during the years. It is not sure that a fish passage runs in any case during its life; some exceptional events (natural or not) can occur, able to modify even in a small scale the fish passage structure negatively affecting its effectiveness. This is the motivation because it is important to do monitoring campaigns, in order to verify the efficiency of the infrastructure during the years, first allowing the fish to localize the entrance, then overpass the whole structure and come out without injuries. Thanks to the monitoring activities it is possible to deduce some ecological information about the fish in transit as: the life stage of the fish, the date of the transit and so the period of the year, strange behaviours, the general status of the fish and other information.